Drive Wheel Steering Control to Reduce Turf Tire Scrubbing
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Solution Overview
Problem
Electric turf maintenance vehicles exhibit slower response and unfamiliar performance characteristics compared to hydraulic systems, leading to undesirable tire slip and scrubbing during turns.
Innovation Solution
A traction and steering control system utilizing electronically-controlled motors for each drive wheel, powered by a generator and battery, which receives input from control levers and monitors operational parameters to generate commands that may not be directly proportional to lever positions, ensuring the vehicle turns about designated regions to prevent tire scrubbing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If electric motors are used to power drive wheels, then the vehicle can be powered electrically with reduced emissions, but the response speed is slower and tire slip increases compared to hydraulic systems
Solution Approach 1:
The control system continuously monitors wheel speed, vehicle heading, and control lever position, then adjusts motor commands in real-time to compensate for the slower electric motor response. This closed-loop feedback mechanism allows the system to predict and correct for the inherent lag in electric motor acceleration, achieving response characteristics similar to hydraulic systems while maintaining zero emissions.
Solution Approach 2:
The patent replaces the hydraulic mechanical system with an electric motor system controlled by electronic commands. The controller processes sensor data and generates motor control signals that substitute for the direct mechanical linkage found in hydraulic systems, enabling precise control of electric motors to match the responsive behavior of traditional hydraulic ZTR vehicles.
2Object-affected harmful factors
If electric motors are used to power drive wheels, then the vehicle can operate with reduced emissions, but tire scrubbing increases during turns
Solution Approach 1:
The control system uses feedback from wheel speed sensors and heading sensors to detect tire slip conditions during turns. When slip is detected, the controller adjusts motor commands to reduce the speed differential between wheels or modify turn geometry, thereby minimizing tire scrubbing while maintaining the benefits of electric propulsion.
Solution Approach 2:
The system dynamically adjusts motor commands based on real-time operating conditions, including turn radius, vehicle speed, and wheel slip. This dynamic control allows the electric motors to adapt their torque and speed output to optimize turning performance and reduce tire scrubbing, compensating for the different acceleration characteristics of electric motors compared to hydraulic systems.
3Ease of operation
If control commands are directly proportional to lever positions, then the system is simple to control, but the vehicle does not account for operational parameters like wheel slip and heading
Solution Approach 1:
The control system maintains simple lever-based operator input while adding sensor feedback loops that monitor wheel speed, vehicle heading, and control lever position. The controller processes this feedback information to generate refined motor commands that account for actual vehicle behavior, ensuring accurate control even when operating conditions differ from ideal scenarios.
Solution Approach 2:
The controller acts as an intermediary between the simple lever input and the complex motor control requirements. It translates straightforward operator commands into sophisticated motor control signals that incorporate sensor feedback, effectively bridging the gap between simple operation and reliable, accurate vehicle control without requiring complex input devices.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system provides responsive turning and reduces tire slip by adjusting wheel power independently, maintaining intended vehicle headings and minimizing tire scrubbing, even at high speeds and challenging terrain.
Implementation Method 1
The traction and steering control system includes one or more of a generator and a battery adapted to power the first and second electronically-controlled motors
Implementation Method 2
The traction and steering control system includes one or more of a generator and a battery adapted to power the first and second electronically-controlled motors
Implementation Method 3
first and second motors connected to the first and second drive members, respectively... the first and second motors may be first and second electronically-controlled motors, respectively
Data Source
AI summary
A traction and steering control system and method for a small- or zero-radius-turning maintenance vehicle. The traction and steering control system may determine operator intended speed and direction by monitoring positions of speed and directional control members and one or more operational parameters of the vehicle. The vehicle may then generate drive wheel speed commands that achieve the intended speed and direction by determining how best to manipulate the left and right drive wheels. In some instances, the drive wheel speed commands are disproportionately related to the positions of the speed and directional control members.